Partial views vs view components — ASP.NET Core MVC (and Razor Pages)

10. Partial views vs view components

Intermediate★ Must knowLesson 10 of 15

	Partial view	View component
Logic	None (just markup with a model you pass)	Has its own C# class with `InvokeAsync` — can call services
Data	Parent must supply the model	Fetches its own data
Use	Reusable markup fragments (product card)	Widgets: shopping cart summary, menu, recent posts
Invoke	`<partial name="_Card" model="x" />`	`@await Component.InvokeAsync("Cart")` or `<vc:cart></vc:cart>`

csharp

public class CartViewComponent(ICartService cart) : ViewComponent
{
    public async Task<IViewComponentResult> InvokeAsync() => View(await cart.GetSummaryAsync(UserClaimsPrincipal));
}
// View: Views/Shared/Components/Cart/Default.cshtml

Child actions (@Html.Action) from MVC 5 no longer exist — view components replace them.